一个新的抗水稻褐飞虱基因Bph28(t)的精细定位及育种应用研究

The brown planthopper (BPH) of rice, caused by Nilaparvata lugens (St?l) (Homoptera: Delphacidae), has become the first devastating insect pest in rice, and poses a serious threat to food security in China. Planting resistant varieties is the most effective way to control this pest, and utilizating resistant genes is critical for applying molecular breeding techniques to make the breeding of rice with resistance to BPH more efficient. BPH is a migratory insect. Guangxi is their first stopover during its northward migrating after transboundary. Thus, the resistant genes from rice resources in Guangxi have great application values. To construct a BPH control system, it is urgent to breed rice varieties resist to BPH and there is highly significant to map and mine more resistant genes, especially from rice resources of Guangxi. Our research group recently discovered Bph28(t),a new dominant gene resistant to BPH from BP60, which is a local variety from Guangxi. In the present study, on the basis of previous initial gene mapping, fine mapping of the target mapping region of Bph28(t) will be carried out, the DNA sequences of all candidate genes will be isolated by PCR, molecular marker will be developed, and the MAS breeding will be implemented to offer genetic sources and technical support for breeding new rice varieties resistant to BPH. This study will elucidate the mechanism BPH resistance control by Bph28(t), develop 2-4 molecular markers for assisted selection, acquire 6-10 resistant rice lines with Bph28(t) and 6-10 resistance rice lines pyramiding with Bph14 and Bph15.

褐飞虱已成为水稻头号害虫，严重威胁我国的粮食生产安全。培育抗虫品种是防治该虫害最为经济有效的方法，而利用抗性基因是应用分子育种技术高效培育抗虫品种的关键。褐飞虱是一种迁飞性害虫，广西是其"北迁"越境后首站，广西丰富稻种资源中的抗性基因具有重要应用价值，因此，挖掘和利用广西水稻资源中的褐飞虱抗性基因，选育高抗褐飞虱的新品种对于防治褐飞虱具有重要意义。本课题组在前期初步定位的基础上，对来源于广西地方品种BP60中的一个高抗稻褐飞虱显性新基因Bph28(t)进行精细定位、分子标记开发以及MAS育种，为水稻抗稻飞虱新品种培育提供基因来源和技术支持。本项目预期可获得抗稻褐飞虱显性新基因Bph28(t)，基本阐明Bph28(t)对抗褐飞虱的作用机制,开发2-4个便于辅助选择的分子标记，获得含Bph28(t)的水稻育种中间材料6-10份，与抗稻褐飞虱基因Bph14、Bph15聚合的材料6-10份。

褐飞虱已成为水稻头号害虫，严重威胁我国的粮食生产安全。广西是褐飞虱“北迁”越境后首站，因此，挖掘和利用广西水稻资源中的褐飞虱抗性基因，选育高抗褐飞虱的新品种对防治褐飞虱具有重要意义。在前期研究基础上，本研究利用InDel标记方法将水稻褐飞虱抗性基因Bph28(t)成功定位到籼稻品种BP60第4染色体短臂的4M03980和4M04041标记之间的42.8 kb区域内，与Liu等在RathuHeenati籼稻中定位到的抗水稻褐飞虱基因Bph3在第4染色体的同一位点。该定位区域包含4个候选基因，Os04g0201500编码一个氨基酸/多胺转运II型家族蛋白，Os04g0201800编码一个假定蛋白，Os04g0201900 和Os04g0202300都编码凝集素受体激酶，该激酶已被证明与水稻抗褐飞虱相关。通过PCR扩增与DNA测序分析，本研究在BP60定位到的Os04g0201900 和Os04g0202300与日本晴中的基因具有98%的序列相似性，与RathuHeenati品种中的基因具有100%的序列相似性，因此基本阐明了Bph28(t)对褐飞虱的作用机制。通过比较分析BP60与9个感水稻褐飞虱品种（9311，桂7571，75-1-27，BL122，112B，特B，良丰B，IRBB7和IR1552）在定位区域内的序列，本研究发现BP60与其它9个品种的Bph28(t)基因中有SNPs差异，根据SNPs差异开发了2个分子标记用于分子育种过程中跟踪Bph28(t)基因，并利用分子标记辅助育种技术获得了含Bph28(t)的水稻育种中间材料8份及与Bph14，Bph15基因聚合的材料8份。抗褐飞虱基因Bph28(t)成功导入到感水稻褐飞虱的恢复系品种桂恢582和桂7571中，并提高了褐飞虱的抗性水平，桂恢582的抗性分值从8.2降到3.6，桂7571的抗性分值从8.7降到3.8。桂恢582的Bph28(t)BC2F8代渗入系与不育系特A杂交，获得了可用于推广种植的抗稻褐飞虱的杂交稻新品种特优373。综合上述结果，本研究为抗褐飞虱基因Bph28(t)用于水稻分子育种奠定了坚实的工作基础。项目资助发表SCI论文1篇，中文核心期刊论文1篇。